Pacemakers in young patients: 1977

New technique for pacemaker implantation in the upper chest of children and women

A new lateral approach for implanting pacemaker generators in the chest of women and children is described. Using this technique, 83 women and 21 children were operated on with no early or late complications and with good cosmetic results up to 9 years after operation. This technique prevents formation of visible wide scars above the breast in women and prevents thinning or disruption of the chest incision in children. Ages of the women ranged from 19 to 56 years; children, 5 to 18 years. In 23 patients, this technique was used after wound complications had occurred 7 days to 3 years after use of the standard implantation technique.

Pacemakers in children: an update

This report reviews recent pacemaker technological advances as they apply to infants, children, and adolescents. Indications for pacemaker implantation in children have evolved since the 1984 Joint Task Force Guidelines. Recent data show that pacemaker implantation should be strongly considered in patients who have (1) asymptomatic congenital complete AV block with a mean heart rate less than 50 beats/min or other evidence of junctional instability; (2) congenital AV block with long QT interval; or (3) congenital long QT syndrome with bradyarrhythmias, or when conventional beta-blocker therapy is unsuccessful. Permanent pacemaker implantation is not necessarily an effective prophylactic measure against sudden death in patients following their operation who are receiving drug therapy for atrial tachyarrhythmias, and so is not absolutely indicated. New developments in lead technology have made transvenous lead systems more feasible for pediatric use. Because epicardial leads are required for small infants and for cosmetic reasons in some older children, design improvements are needed to enhance epicardial lead performance. Rate-responsive pacing is an acceptable alternative to dual-chamber pacing for augmenting exercise tolerance, and for children with sinus node dysfunction it is the preferred pacing mode. Pacemakers with automatic antitachycardia capabilities and with noninvasive electrophysiology features are valuable in children with atrial tachyarrhythmias. New data suggest that chronic atrial pacing also may be effective in controlling atrial tachyarrhythmias. New developments in pacemaker systems for the young parallel those for the older population, but differences between adult and pediatric patients demand ongoing increased participation by pediatric cardiologists.

Use of ambulatory electrocardiographic monitoring to identify high-risk patients with congenital complete heart block

To define the long-term natural history of congenital complete heart block, we followed 27 patients prospectively by means of frequent ambulatory electrocardiographic (ECG) recordings for a mean (+/- SD) of 8 +/- 3 years. During that time, 8 of the 13 patients with a mean daytime heart rate below 50 bpm (Group A) had cardiac complications such as sudden death, syncope, presyncope, or excessive fatigue. Six of the eight patients had additional ECG findings that suggested an instability of the junctional escape mechanism. These findings included nocturnal junctional exit block (three patients), little or no change in the junctional rate with physical activity (three patients), and associated tachyarrhythmias (three patients). None of the 14 patients with a mean daytime heart rate of 50 bpm or more (Group B) had an adverse clinical outcome, and 5 of the 13 patients in Group A also remained well. Among the five patients in stable condition in Group A, three had no evidence of an unstable junctional mechanism. We conclude that patients with a mean daytime junctional rate below 50 bpm and other evidence of an unstable junctional escape mechanism should probably undergo prophylactic pacemaker implantation. Since junctional exit block and tachyarrhythmias sometimes appear first during follow-up, the method of risk stratification employed in this study depends on serial ambulatory ECG recordings.

Evaluation of pacemaker pulse generator and patient longevity in patients aged 1 day to 20 years

The longevity of pediatric patients requiring pacemakers and the survival rates of the implanted generators were evaluated. From January 1970 to December 1985, 96 patients aged 1 day to 20 years underwent 162 pulse generator implantation procedures. Indication for initial implantation was surgically induced heart block in 52 patients, sick sinus syndrome in 20, congenital complete heart block with symptoms of low cardiac output in 19 and tachydysrhythmia control in 5. Modal age at initial implantation was less than 1 year; median age was 5 years. During this period 90 generators were removed from service: 49 (54%) because of generator failure, 22 (24%) because the patient died, 12 (13%) because of elective upgrade at the time of lead failure or cardiac surgery, 5 (6%) because of generator pocket infection and 2 (2%) because of manufacturer's recall. Pulse generators were separated into 4 groups based upon generator technology. Group I (n = 16) were asynchronous units with mercury-zinc batteries; group II (n = 18) were single-chamber demand units with mercury-zinc batteries; group III (n = 14) were single-chamber demand units with rechargeable batteries; and group IV (n = 114) were single- or dual-chamber demand units with lithium batteries. Patient survival rate was 84% at 6 months and 70% by 109 months. There was no further decrease to the end of the study period. Six-month generator survival rate was 82% for all groups, mostly a reflection of patient deaths.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac pacing in children

Twenty patients aged between 12 months and 13 years underwent permanent pacemaker implantation. The main indication for pacing was post-surgical atrioventricular block. The complication rate was high and related mainly to infections and lead system problems. The use of small multiprogrammable pacemakers is expected to reduce the reoperation rate for system malfunction and elective replacement. Newer methods of electrode insertion and active fixation devices in smaller diameter leads make endocardial pacing a practical alternative to epicardial pacing in the larger child who did not require a pacing system at the time of surgery.

Long-term endocardial atrial pacing in children with postoperative bradycardia-tachycardia syndrome and limited ventricular access

Permanent pacing in children, including those with postoperative bradycardia-tachycardia syndrome has been compromised by the availability of pulse generators, electrode leads and implantation techniques designed for the adult patient. Recent technologic improvements and simplified implantation techniques have reduced many of these barriers and have made endocardial as well as epicardial ventricular pacing more feasible. However, in some children, ventricular pacing may be impeded by anatomic abnormalities due to congenital anomalies or prior cardiac operations. In these instances, endocardial atrial pacing may provide an alternative therapeutic approach in selected patients. This report describes the use of endocardial atrial demand pacing in four children with postoperatively bradycardia-tachycardia syndrome and restricted ventricular access. This approach controls symptomatic bradycardia, helps prevent and convert paroxysmal intraatrial tachycardia and overcomes the problems of limited ventricular access.

Comparison of the sutureless and suture-type epicardial electrodes in pediatric cardiac pacing

Fourteen consecutive patients with the suture-type electrode (Group 1) were compared with the previous 14 patents having the sutureless electrode (Group 2). five patients in Group 1 had had failure with the sutureless electrode, for a total of 23 patients. In Group 1, no exit block was encountered. One patient had sensing problems corrected simply by increasing the pacer rate. One patient had generator failure and another, lead fracture. In 5 patients in Group 2, exit block developed early (less than 6 months after implantation); 3 patients had the problem twice, making a total of eight early failures. Two patients had late exit block (more than 6 months after implantation). Improved results with the suture-type electrode can probably be explained by its smaller head, larger surface area, ease of placement in a small space, and control of direction and depth of implantation.

Review article. Congenital complete heart block

Isolated congenital complete heart block has a heterogenous aetiology. In approximately one-third of the patients in the present material the mothers had symptoms or signs of connective tissue disease. The mortality is highest in the neonatal period, much lower during childhood and adolescence and increases slowly later in life. There are elderly patients who are completely asymptomatic but patients are also encountered with signs and symptoms of more or less severe myocardial damage. Stokes-Adams attacks may occur at any age. About 10% of patients below 15 years of age in this material and about 25% of those above 15 years (mean age 30 years) were paced. In the neonatal period the predominant indication for pacing was heart failure. It is difficult to make a prognosis in the individual patient. Apart from already known risk factors, a fixed or decreasing low ventricular rate neonatally and a prolonged QT time seem to be bad prognostic signs.